Electric vehicles are becoming an increasingly viable alternative to traditional vehicles with internal combustion engines. Electric vehicles have the advantages of compactness, simplicity of design, and being potentially more environmentally friendly, depending on the method by which the electricity used in the electric vehicle was originally generated. The prospect of using renewable energy sources to power automobiles in place of gasoline has obvious advantages as oil reserves across the globe become increasingly depleted.
Manufacturers of electric vehicles and/or hybrid vehicles generally take one of two approaches in configuring an electric motor into a vehicle. The first approach is to place the electric motor in the vehicle in either parallel with the internal combustion engine or in place of the internal combustion engine, thus utilizing the existing structure of the transmission system and gear box to deliver power to the axles and wheels. The second approach is to place the electric motor directly in the internal cavity of the wheel. In-wheel motors have the advantage of being highly simple and compact. The disadvantages of such a system are that the extra weight placed within the wheel increases the unsprung mass of the vehicle which adversely affects the vehicle's ride and handling.